Pediatric Ophthalmology and Strabismus — MCQs

Pediatric Ophthalmology and Strabismus Indian Medical PG Practice Questions and MCQs

Question 281: Crossed eye fixation is positive in -

A. Esotropia (Correct Answer)
B. Exotropia
C. Hypertropia
D. Hypotropia

Explanation: ***Esotropia*** - **Crossed eye fixation** is a characteristic sign observed in infants with **infantile esotropia**, where one or both eyes are turned inward. - In this phenomenon, the infant uses the **adducted (turned-in) eye** to fixate on objects in the **temporal visual field** of that eye, rather than using the normally positioned fellow eye. - This represents an **abnormal fixation pattern** where the child "crosses fixation" by using the esotropic eye to view objects that would normally be seen by the other eye. - This is a compensatory mechanism and a clinically important sign in **pediatric strabismus evaluation**. *Exotropia* - **Exotropia** involves an outward deviation of one or both eyes (divergent strabismus). - Crossed eye fixation is **not characteristic** of exotropia; this condition shows different fixation patterns. *Hypertropia* - **Hypertropia** is an upward vertical deviation of one eye relative to the other. - Crossed eye fixation is a **horizontal fixation phenomenon** and does not manifest in vertical deviations. *Hypotropia* - **Hypotropia** is a downward vertical deviation of one eye relative to the other. - This vertical misalignment does not present with the specific finding of crossed eye fixation.

Question 282: Onset of stereopsis occurs at the age of:

A. 3 to 5 months (Correct Answer)
B. 1 to 2 years
C. 5 years
D. 7 years

Explanation: ***3 to 5 months*** - **Stereopsis**, or **binocular depth perception**, typically develops between **3 to 5 months of age** as the visual system matures and the brain learns to fuse images from both eyes. - This developmental window is crucial for the establishment of normal **depth perception** and is actively assessed during infant visual screenings. *1 to 2 years* - While visual development continues beyond infancy, the **onset of stereopsis** occurs earlier, in the first few months of life, not between 1 to 2 years. - At 1 to 2 years, children are further refining their **hand-eye coordination** and **visual-motor skills**, building upon established **depth perception**. *5 years* - By **5 years of age**, a child's visual system, including stereopsis, should be fully developed, and any significant deficits in **depth perception** at this stage would indicate a developmental problem. - This age represents a mature stage of visual function, not the **initial onset** of stereopsis. *7 years* - At **7 years of age**, the visual system is considered fully mature, and any significant issues with **stereopsis** would likely indicate a long-standing, uncorrected visual impairment that developed much earlier. - The critical period for the development of stereopsis has long passed by this age.

Question 283: In the context of ophthalmology, what does the acronym BSGT refer to?

A. Bagolini striated glasses test (Correct Answer)
B. Bagolini smooth glasses test
C. Bagolini shiny glasses test
D. Bagolini stereoscopic glasses test

Explanation: ***Bagolini striated glasses test*** - The acronym **BSGT** specifically refers to the **Bagolini striated glasses test**, which is a method used in ophthalmology and optometry to evaluate a patient's binocular vision and determine the presence and type of **diplopia** or **suppression**. - This test uses special lenses with fine, parallel striations that cause a point source of light to appear as a streak, helping to assess the patient's **correspondence** and **fusion abilities**. *Bagolini smooth glasses test* - The term **"smooth glasses test"** is not a recognized or standard test in optometry. - The distinctive feature of Bagolini lenses is their **striations**, which are critical for the test's function. *Bagolini shiny glasses test* - The term **"shiny glasses test"** is not a recognized or standard test in optometry. - The appearance of the glasses as **"shiny"** does not convey the functional aspect of the test's striations. *Bagolini stereoscopic glasses test* - While the Bagolini test assesses aspects of binocular vision and can indirectly relate to **stereopsis**, it is not primarily called a **"stereoscopic glasses test."** - **Stereoscopic tests** typically use polarized or red-green anaglyph lenses to directly evaluate depth perception, which is distinct from the primary goal of the Bagolini test.

Question 284: Which muscle paralysis causes right esotropia?

A. Left medial rectus paralysis
B. Right medial rectus paralysis
C. Right lateral rectus paralysis (Correct Answer)
D. Left lateral rectus paralysis

Explanation: ***Right lateral rectus paralysis*** - **Esotropia** is an inward deviation of the eye. A paralyzed **right lateral rectus muscle** would prevent the right eye from abducting (moving outward), causing it to turn inward. - The **lateral rectus muscle** is responsible for abducting the eye, and its paralysis would result in an unopposed pull by the medial rectus, leading to esotropia. *Left medial rectus paralysis* - Paralysis of the **left medial rectus** would prevent the left eye from adducting (moving inward), resulting in an **exotropia** (outward deviation) of the left eye, not right esotropia. - The **medial rectus muscle** adducts the eye, and if paralyzed, the eye would drift outward. *Right medial rectus paralysis* - Paralysis of the **right medial rectus** would prevent the right eye from adducting, leading to an **exotropia** (outward deviation) of the right eye, not an esotropia. - This muscle is responsible for moving the eye inward, and its dysfunction would cause the eye to deviate outwards. *Left lateral rectus paralysis* - Paralysis of the **left lateral rectus** would cause the left eye to deviate inward (left esotropia), as the eye would be unable to abduct. - This condition affects the left eye, not the right eye as indicated in the question.

Question 285: A 65-year-old male with a history of hypertension and diabetes presents to the OPD with complaints of diplopia and squint. On examination, the secondary deviation is more than the primary deviation. Which of the following is the most likely diagnosis?

A. paralytic squint (Correct Answer)
B. concomitant strabismus
C. restrictive strabismus
D. pseudo strabismus

Explanation: ***Paralytic squint*** The key finding of **secondary deviation being greater than primary deviation** is a classic sign of **paralytic strabismus**. This occurs because the paretic eye (due to neurological deficit) has to work harder to fixate, leading to an exaggerated innervation to the yoked muscle in the healthy eye, causing a larger deviation (Hering's law of equal innervation). The patient's age and history of **hypertension and diabetes** increase the risk of **cranial nerve palsies** (e.g., oculomotor, trochlear, abducens), which are common causes of paralytic squint due to microvascular ischemia. *Concomitant strabismus* In **concomitant strabismus**, the degree of deviation remains constant in all directions of gaze, meaning **primary and secondary deviations are equal**. This contradicts the clinical finding in the patient. Concomitant strabismus often presents in childhood and is typically non-paralytic, with no underlying neurological deficit affecting muscle action. *Restrictive strabismus* **Restrictive strabismus** is characterized by physical limitation of eye movement due to mechanical restriction of an extraocular muscle, often seen in conditions like **thyroid eye disease** or **orbital trauma**. While restrictive strabismus can cause diplopia and reduced eye movement, it typically involves a **limited range of motion** and usually does not present with secondary deviation being greater than primary deviation in the same manner as a paralytic squint. *Pseudo strabismus* **Pseudo strabismus** is an apparent misalignment of the eyes where the eyes are actually straight. This can be due to features like a **wide epicanthal fold** or a **small interpupillary distance**. In pseudo strabismus, there is **no true deviation** on cover-uncover testing, and therefore, the concepts of primary and secondary deviation do not apply, nor would there be actual diplopia.

Question 286: Esotropia is usually associated with:

A. Nearsightedness
B. Farsightedness (Correct Answer)
C. Irregular cornea shape
D. Age-related vision loss

Explanation: ***Farsightedness*** - **Esotropia**, or convergent strabismus, is often associated with **farsightedness** (hyperopia) because the extra focusing effort required to see clearly at near distances can lead to inward turning of the eyes. - The accommodative effort to overcome hyperopia can cause an **overconvergence** of the eyes, resulting in esotropia. *Nearsightedness* - **Nearsightedness** (myopia) is more commonly associated with **exotropia** (eyes turning outward) or no strabismus. - Myopia generally requires less accommodative effort, which would not typically lead to convergent strabismus. *Irregular cornea shape* - An **irregular cornea shape** is characteristic of **astigmatism**, which causes blurred or distorted vision. - While astigmatism can contribute to visual strain, it is not directly or primarily associated with esotropia. *Age-related vision loss* - **Age-related vision loss** typically refers to conditions like **macular degeneration**, cataracts, or presbyopia. - These conditions affect visual acuity but do not directly cause esotropia, which is a misalignment of the eyes.

Question 287: Strabismic amblyopia is more common in patients with:

A. Constant strabismus (Correct Answer)
B. Alternating strabismus
C. Latent strabismus
D. Intermittent strabismus

Explanation: **Constant Strabismus** - In **constant strabismus**, one eye is always deviated, leading to **continuous suppression** of the image from the deviated eye by the brain. - This consistent suppression prevents proper visual development in the deviated eye, resulting in **amblyopia**. *Alternating strabismus* - In **alternating strabismus**, the deviation switches between the two eyes, allowing each eye to take turns fixing. - This alternation helps maintain relatively good visual acuity in both eyes, making **amblyopia less common** or severe. *Latent strabismus* - **Latent strabismus** (phoria) is a deviation that is only present when binocular fusion is disrupted (e.g., when one eye is covered). - Since fusion is typically maintained in daily vision, there is **no constant suppression** of one eye, and amblyopia is rare. *Intermittent strabismus* - **Intermittent strabismus** involves periods of deviation alternating with periods of straight eye alignment, often varying with fatigue or visual tasks. - While it can lead to amblyopia, it is **less common and severe** than with constant strabismus because there are periods when the visual input from both eyes is utilized.

Question 288: The most common type of strabismus seen in myopes is?

A. Intermittent Exotropia (Correct Answer)
B. Intermittent Esotropia
C. Esotropia Hypotropia complex
D. Exotropia Hypotropia complex

Explanation: ***Intermittent Exotropia*** - Myopes often employ less **accommodative effort** for near tasks, leading to reduced **accommodative convergence** and an increased tendency for the eyes to drift outwards. - This outward deviation, or **exotropia**, is frequently intermittent, especially during fatigue or inattention. *Intermittent Esotropia* - **Esotropia** is an inward turn of the eye and is typically associated with **hyperopia** due to excessive accommodative effort leading to increased accommodative convergence. - While it can be intermittent, it is not the most common form of strabismus in myopic individuals. *Esotropia hypotropia complex* - This complex involves both an inward deviation (**esotropia**) and a downward deviation (**hypotropia**). - It is not typically seen in healthy myopes and would suggest other underlying **neurological** or **structural abnormalities**. *Exotropia Hypotropia complex* - While **exotropia** can be common in myopes, the additional presence of **hypotropia** (downward deviation) suggests a more complex strabismic picture. - This combination is not the most frequent strabismus seen in uncomplicated myopia and may indicate **cranial nerve palsies** or **orbital anomalies**.

Question 289: Forced duction test is to find out?

A. Ocular muscle palsy
B. Ocular muscle spasm
C. Angle of deviation
D. Mechanical restriction of eye movement (Correct Answer)

Explanation: ***Mechanical restriction of eye movement*** - The forced duction test is specifically designed to **detect mechanical restriction** that prevents free passive movement of the globe. - Performed under **topical anesthesia**, the examiner grasps the eye at the limbus with forceps and attempts to passively rotate it in the direction of limited motility. - A **positive test** (resistance to passive movement) indicates mechanical restriction from causes like **thyroid-associated orbitopathy, orbital floor fracture, entrapment, or fibrosis**. - This is the **primary clinical indication** for performing the test - to differentiate restrictive from paretic causes of strabismus. *Ocular muscle palsy* - In muscle palsy (paretic strabismus), the forced duction test is **negative** - the eye moves freely with passive movement. - The test helps **differentiate paretic from restrictive causes** of limited motility, but the test itself detects restriction, not palsy. - Free passive movement confirms that the limitation is due to muscle weakness rather than mechanical factors. *Ocular muscle spasm* - Active muscle spasm would not be detected by this test because it is performed **under topical or general anesthesia**, which eliminates active muscle contraction. - The test assesses **passive mechanical restriction**, not active muscle activity or spasm. - Spasm would be a neurogenic rather than mechanical cause and would show free passive movement on testing. *Angle of deviation* - The forced duction test does not measure the **degree or angle of deviation** in strabismus. - Tests like the **prism cover test** or **Hirschberg test** are used to quantify deviation. - The forced duction test provides qualitative information about the cause of limitation, not quantitative measurement of misalignment.

Question 290: Normal level of visual acuity is attained at which age

A. 6 months
B. 1 year
C. 3 years
D. 6 years (Correct Answer)

Explanation: ***6 years*** - **Normal adult visual acuity (20/20 or 6/6)** is typically achieved around the age of **6 years** as the visual system fully matures. - This age allows for the complete development of **foveal vision** and **binocular functions**. *6 months* - At 6 months of age, an infant's visual acuity is still developing and is typically around **20/200 to 20/400**. - While significant visual development occurs by this age, including **face recognition and tracking objects**, it is not yet at adult levels. *1 year* - By one year, visual acuity improves to approximately **20/50 to 20/100**. - Infants at this age are able to **distinguish fine details** and have improved **depth perception**, but full maturity is still some years away. *3 years* - At 3 years of age, visual acuity is generally around **20/30 to 20/40**. - Children at this stage are able to perform **visual tasks** like drawing and recognizing letters, but subtle refinements are still ongoing.

Practice by Chapter

Amblyopia

Practice Questions

Esotropia

Practice Questions

Exotropia

Practice Questions

Vertical Deviations

Practice Questions

Special Forms of Strabismus

Practice Questions

Nystagmus in Children

Practice Questions

Pediatric Cataract

Practice Questions

Retinopathy of Prematurity

Practice Questions

Pediatric Glaucoma

Practice Questions

Pediatric Neuro-ophthalmology

Practice Questions

Genetic Eye Diseases in Children

Practice Questions

Pediatric Ocular Trauma

Practice Questions

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